Intradialytic blood pressure (BP) variability may be associated with increased mortality. We examined the effect of short daily hemodialysis (SDHD) on intradialytic BP variability relative to conventional thrice-weekly HD (CHD). This is a retrospective cohort study. Subjects were those converted from CHD to SDHD (n=12). All intradialytic BPs were collected on the last month of CHD, and on month 6 of SDHD. Absolute predialysis BP level and intradialytic BP variability were defined as the intercept and average residual terms, respectively, from a mixed-effects linear regression model of time on BP. Dialysis modality was a predictor variable (CHD vs. SDHD). Outcome variables were intradialytic BP variability and hypotension (BP<90/55 mmHg at any time during HD). In addition to a predictor and outcomes, the demographics, estimated dry weight, and ultrafiltration ratio were examined. The median (range) age of the patients was 48 (34-77); all had hypertension, and 4 (33%) had diabetes. By a mixed effects linear regression model, the intradialytic systolic BP variability was 13.2 (quartile range 9.5-14.0) mmHg and 10.0 (8.3-10.9) mmHg for CHD and SDHD, respectively (P<0.006). Intradialytic diastolic BP variability was also significantly reduced (7.7 [6.4-9.2] vs. 6.1 [5.5-6.6] mmHg, P=0.005). Relative to CHD, less hypotension was observed during treatment on SDHD: the odds ratio (95% confidence interval) was 0.36 (0.16-0.81; P=0.008). In this retrospective study, SDHD was associated with less intradialytic BP variability and with fewer episodes of hypotension during treatments. Further studies are necessary to generalize these findings.